1. Field of the Invention
This invention relates to a dental treatment apparatus provided with a check valve in a fluid passage thereof and, more particularly, to a dental treatment apparatus provided with a check valve for minimizing the fluid suction to be caused when terminating the dental treatment operation.
2. Related Art Statement
In currently used dental treatment apparatuses, there is included a fluid suction device such as a pull-back control valve having the function to pull back the pressurized fluid to suck the fluid so as to prevent the fluid from flowing down at the extreme end of the handpiece when the supply of the pressurized fluid is terminated. However, since this suction device sucks up about 1 ml of air, the patient's saliva and cut chips produced by the cutting tool provided to the dental handpiece are sucked simultaneously so as to be then discharged into the next patient's oral cavity. This is not only undesirable from the viewpoint of hygienics but also may give rise to cloging of the water supply passage.